Early Apple Keyboards
1 computers did not come with a keyboard. The operations manual did
specify what could be used: "Any ASCII encoded keyboard, with positive DATA outputs,
interfaces directly with the Apple system via a "DIP" connector."
The Datanetics keyboard was probably pressed into service with an Apple
1 more frequently than any other kind. In fact there is evidence that Steve Jobs of Apple recommended this keyboard.
The image above is a Datanetics rev B. It used a National MM5740/AAE decoder chip.
The data book and app. notes for this part can be downloaded from here.
More technical information about this keyboard can be found on my Datanetics page.
This keyboard was apparently being or completed manufacturing on
May 28,1976 and based on the markings, could be serial #10. I
believe that the DC stands for Datanetics Corporation.
The Datanetics Corporation made their own keyswitches which were patented (#3777090). The patent can be found here
and includes a detailed description of the operation of this keyswitch.
Here is an image of the keyswitch. Identical keyswitches
exist with a straight stem, but it is not known what products, if any,
they were used in.
Datanetics keyboard had a unique feature that allowed the
user to wire 4 "blank" keys to any decoded character desired.
This was done by connecting the row and column using the matrix
on the top and bottom of the upper left side of the PCB. The
holes in this matrix were not plated, so there was no connection
between top and bottom copper layers unless the user ran a wire through
the hole. What follows is a CAD image of a reproduction I'm
working on, showing how the matrix was connected to keys 27, 41, 54 and
56 (the blank keys). The blue traces are on the back layer and
lead to the key switches. The red traces are on the front of the
PCB and lead to the keyboard encoder chip.
These blank keys were also connected to the edge connector on
the upper right side of the keyboard so other user functions could be
Apple 1 had two keyboard controlled functions that were a bit
unusual. First was the fact that the prom monitor used underscore
the backspace/rubout feature. The other was a clear screen
function that required the clear screen input signal to be pulled up to
+5 volts to clear the screan. The clear screen function could be
datanetics keyboards by properly connecting a blank key from the edge
connector to the 16 pin DIP port. My current understanding is
that the underscore is not implemented in the MM5740/AAE chip, so there
was no way to use the Apple 1 monitor backspace feature with this
Photo courtesy of Cliff & Dick Huston from EarlyApple Ebay Auction, March 2010
rather rapidly and later versions had some changes, including a solder
mask. Here is an image of a rev D. Note the keycap shaped
power indicator light. Other changes include bigger shift
and return keys and arrows instead of rubout key. This keyboard
is very similar to the first Apple II keyboard seen in next section.
Remember that other manufacturers keyboards were
frequently used with the
Apple IIApple II's initially came either as
motherboards without keyboard, case or power supply or as complete
computers. If you purchased a motherboard, you had to find your
own keyboard. Most parallel ASCII encoded keyboards available at the time could be
interfaced to an Apple II motherboard, including the Datanetics.
first keyboard supplied with the Apple II is shown above. It was
apparently made by Datanetics for Apple, as the keyswitches are
Datanetics patented keyswitches identical to those used on the earlier
Datanetics keyboards. However there is no manufacturer identified
on the board itself to prove that Datanetics actually made it. The
layout is very similar to the rev D datanetics show above. This
keyboard came with Apple II serial number 2672. Also the
manufacturing date and serial stamps are similar to the Rev B
Datanetics. This one was stamped March 2, 1978 and has an
apparent serial number of 2779.
keyboard also used the MM5740/AAE keyboard encoder. This keyboard had
an edge conector, which had a different pinout from the
datanetics edge connector. This edge connector is rarely used on
an Apple II. When the
top of the computer case was removed, the top edge of the keyboard
extetended a bit into the opening. The combination of this
extension, the edge connector and the MM5740/AAE led to
serious problem with static charges frying the MM5740 encoder on these
introduced roughly around serial number 3000 of the Apple II
production. This version is electically identical to the first
version. However the MM5740 was moved and the exposed edge
was removed. This is an apparent attempt to eliminate the problem
with static charges destroying
decoders. This change eliminated the extension that
extends into the area of the enclosure that is exposed when the cover
example was dated Jul 20, 1979, right around the beginning of A2 plus
production. The keyboard came with A2 plus serial number 2737
which I purchased off of ebay. The interesting thing about it is
the dome power light. I've seen earlier serial numbered A2 plus
systems listed on ebay that have a square power light. I suspect
the serial number is 29876, but it is hard to know if this is a
correct assumption and when the numbering started.
Version 2 Keyboard Production ChangesI have a later copy of the second version keyboard and it is different from the first in several ways.
Power Light ChangeApparently
during production of this second
version keyboard, the power light was switched to a raised square
light. I have speculated that this indicator was changed because
might have confused this indicator with an actual power switch.
The dome light is on the early keyboard and the square light is
on the later one.
image below shows the manufacturing markings on this later production
copy. It seems that it was stamped by manufacturing on Nov
29, 1979 and had a possible serial number of 148164.
light, another difference between these versions is the
solder mask, which is brown on the second version. These two
boards were clearly made by different PCB fab houses. Electical
function seem identical.
Apple II and Apple II plus System DifferencesThere
was significant overlap in production time of the Apple II and Apple II
plus. During this overlap, the only difference between the
machines was the programs loaded into the ROMs. The very first
Apple II plus systems have the second version keyboard.
End of the MM5740/AAE EncoderWith the next version keyboard,
the MM57040/AAE encoder was replaced by a separate plug in encoder that
contained a SMC KR3600 encoder.
First RFI VersionThis keyboard is the first version that was RFI compliant.